The maintenance of future fusion reactors will depend on robotic systems that require various electronic components for sensing, power and control. However, current silicon-based electronics do not offer sufficient resistance to the radiation present in these environments. Wide bandgap semiconductors, like gallium nitride (GaN), are characterised by high bond dissociation energies, making them less vulnerable to radiation-induced displacement damage. By also optimizing the architecture of these devices, it is possible to further extend their operational lifespan in high-radiation settings, thereby reducing the cost and frequency of replacements.
My PhD project, investigates the performance of nitride high electron mobility transistors (HEMTs) fabricated in-house after exposure to very high doses of radiation (up to and beyond 1MGy), as well as exploring the behaviour of more novel HEMT structures. This includes incorporating porous layers to absorb particulate radiation, such as neutrons, to further improve radiation resistance. The impact of high radiation doses on the devices main performance metrics will be studied using magneto-transport measurements, while radiation-induced defects in the materials will be characterised using techniques such as cathodoluminescence and scanning probe microscopy.
